Screening of Yeasts for Selection of Potential Strains and Their Utilization for In Situ Microbial Detoxification (ISMD) of Sugarcane Bagasse Hemicellulosic Hydrolysate

Author(s)

Soares, Luma C. S. R. ^[1] ; Chandel, Anuj K. ^[1] ; Pagnocca, Fernando C. ^[2] ; Gaikwad, Swapnil C. ^[1] ; Rai, Mahendra ^[3] ; da Silva, Silvio S. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Engn Lorena, Dept Biotechnol, BR-12602810 Lorena, SP - Brazil

^[2] UNESP, Biosci Inst Rio Claro, Dept Biochem & Microbiol, BR-13506900 Rio Claro, SP - Brazil

^[3] SGB Amravati Univ, Dept Biotechnol, Amravati 444602, Maharashtra - India

• Document type: Journal article
• Source: INDIAN JOURNAL OF MICROBIOLOGY; v. 56, n. 2, p. 172-181, JUN 2016.
• Web of Science Citations: 4

Abstract

Many toxic compounds are produced and released in the hemicellulosic hydrolyzates during the acid pretreatment step, which are required for the disruption of the lignocelluloses matrix and sugars release. The conventional methods of detoxification i.e. overliming, activated charcoal, ion exchange or even membrane-based separations have the limitations in removal of these toxic inhibitors in fermentation process. Hence, it is imperative to explore biological methods to overcome the inhibitors by minimizing the filtration steps, sugar loss and chemical additions. In the present study we screened sixty-four strains of yeasts to select potential strains for detoxification of furfural, acetic acid, ferulic acid, 5-hydroxymethyl furfural (5-HMF) as carbon and energy source. Among these strains Pichia occidentalis M1, Y1'a, Y1'b and Y3' showed a significant decrease in the toxic compounds but we selected two best yeast strains i.e. P. occidentalis Y1'a and P. occidentalis M1 for the further experiments with an aim to remove the fermentation inhibitors. The yeasts P. occidentalis Y1'a and P. occidentalis M1 were grown aerobically in sugarcane bagasse hemicellulose hydrolysate under submerged cultivation. For each yeast, a 2(2) full factorial design was performed considering the variables-pH (4.0 or 5.0) and agitation rate (100 or 300 rpm), and the percentage removal of HMF, furfural, acetic acid and phenols from hemicellulosic hydrolysates were responsive variables. After 96 h of biological treatment, P. occidentalis M1 and P. occidentalis Y1'a showed 42.89 and 46.04 % cumulative removal of inhibitors, respectively. (AU)

• FAPESP's process: 08/57926-4 - Research and development aiming at the integrated exploitation of sugarcane bagasse for the biotechnological production of lignocellulosic ethanol
• Grantee: Silvio Silvério da Silva
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 10/13828-9 - Fermentative process to obtaining second GENERATIOL ethanol from sugarcane hemicellulosic hydrolysate in a basket type STR bioreactor using immobilized cells
• Grantee: Thais Suzane Milessi Esteves
• Support Opportunities: Scholarships in Brazil - Master